Hormone Replacement Therapy (HRT) is a medical treatment that involves the use of one or more of a group of medications designed to increase hormone levels in women who lack adequate hormone production. HRT can mitigate and prevent symptoms caused by diminished circulating estrogen and progesterone hormones in a pre-menopausal, peri-menopausal, menopausal, or post-menopausal subject.
Progesterone (CAS#57-83-0), also known as P4 (pregn-4-ene-3,20-dione), is a C21 steroid hormone involved in the female menstrual cycle, pregnancy, and embryogenesis of humans and other species. Progesterone belongs to a class of hormones called progestogens, and is the major naturally occurring, endogenous human progestogen. The use of progesterone and its analogues has many medical applications, both to address acute conditions as well as the long-term decline of natural progesterone levels. Undesirable side effects exist due to irregular, inconsistent, or decreased hormone production in pre-, peri-, menopausal, and post-menopausal females. Progesterone is indicated for use in the prevention of endometrial hyperplasia in non-hysterectomized postmenopausal women who are receiving estrogen tablets. Progesterone is also indicated for use in secondary amenorrhea.
Estradiol (CAS#50-28-2), also known as 17β-estradiol, oestradiol, or E2, is found endogenously in the human body and is the primary female sex hormone. Estradiol contributes to regulation of estrous and menstrual reproduction cycles in females, development of reproductive tissues, and maintenance of bone tissue, among other processes. Estradiol deficiency in female subjects is implicated in conditions such as preterm birth, sleep disturbances, mood changes, vulvo-vaginal atrophy, and osteoporosis.
Existing topical transdermal compositions are formulated such that high dosages of hormones are administered, and they suffer from progesterone's limited absorption and bioavailability. Therefore, new transdermal pharmaceutical compositions for more effective delivery of progesterone and other hormones including estradiol are needed. The invention disclosed herein meets this and other needs.